DESCRIPTION: Significant increase in the efficiency and speed of MS-based tissue imaging (IMS) performed at atmospheric conditions using high-resolution mass spectrometer will have a profound impact on method applications to the entire analytical field of characterization of biomarkers in tissues. At present, the efficiency of the MS-based tissue imaging is limited by low sensitivity. We propose to employ a separate post-ionization step to increase the ion yield from the material ablated by laser from the tissues. To demonstrate high-throughput IMS analysis based on the proposed post-ionization technique, we plan to modify the house-built compact UV laser system capable of generation high-intensity laser pulses at very high repetition rate.